2-naphthyl j-acid and the urethanes thereof as color formers



Patented Aug. 30, 1949 I UNI TLEED PATENT O F F l C E 2-NAPH'IHYL J -ACID AND TH'E URETHANES THEREOF AS COLORTFORMERS 'Vsev'tilod 'Tulagin, "Phillipsburg, "N. .1., "and Willy A. Schmidt, Easton, Pa., aa'ssignors 1:0 General Aniline & Film Corporation, New York, .N. Y.,' :acorporation :of Delaware No Drawing. Application May 6, 1948,

"Serial No. 25,534

5 Claims.

The present invention relates to color photogand more particularly to the preparation :of dye images in a photographic element "while rutilizin'g in either the photographic emulsion or the developer 2- nap'hthy'l J-acid -'or a urethane thereof.

It :is well known in the art that one of the commonest rand best methods for producing dyeastuff images :in photographic silver halide emulsion :is that known as 'color f'orming development. process is predicated .upo'n th'e utilization of a e'compound montaining either a zphenolic hydroxyl group or .a xrea'ctive methylene .group to couple with thepxidation products "of a primary aromatic amino developer to produce :in situ with the silver image formed "on development (of -a z'quinoneimine or azome'thine *dyestufi.

J acid=and its derivatives-are widely employed as dye intermediates, particularly .in the prepa- :ration of azo dyes. J acid :has the following iiormula:

theN-phenyl and acyl derivatives, are characfteiiz'd theiact that they are capable (if -profinding deeply colored dyes or high tinctorial strength. Because of this pro erty and their "ability to form Iquinoneimih'e dyes, these compounds would normally recommend "themselves for use in color photography as 'colorffoimers. Tlnfortunatelyflhowever, J-acid itself and its 'fN phenyl derivatives, are not s'u'ffi'c'rently stable ffrom'a chemical standpdintto resist the bleach- *ing or "oxidizingbaths employed to remove metallie "'silver'i'n the'proces's'ing of color ffilm. 'Thus, experience has shown that although th'edyas derivedfrom the J-"ac'idsby color formingdeve'lop- 'ine'nt "are highly stable, the'se intermediates cannot as such be incorporated in a photographic emulsion since they yield strongly colored yel- Haw brown dya when subjected to oxidizing agents necessary for the removal of the silver image and that, th'ereiore, any film containing them would be uniformly dyed a "yellow brown upon the eom'pietien or the process. "This, of course makes impossible to obtain "a coidfless fir -White p6l' ti0h in the finishedimage.

"We have new discovered that the heretofore uninvestigated Z-n'aphthyl :J-acid and the urethan'es th'ereo'f possess all of the desirable oh'aracteristi'cs of J-acid '01 its known derivatives without their attendant disadvantages. For instance, said Z-naphthyl J-acid and its urethanes are stable intermediates, .easily obtained .in a chemically pure condition. When -used for the syntheses of dyes, they produce brilliant shades showing .a marked 'ba'thochromatic shift in the transmission spectra when compared with analogous dyes derived from phenyl'J-acid and its derivatives. We have also learned that'dyes obtainedlfrom '2-naphthyl ZI-acid andits urethanes possess improved light stability and greater substantivity toward organic .fibers, gelatin and other organic coatings.

The urethanes of Z-napht'hyl J-acid, moreprepare soluble 'an'd'wlren provided witha long faliphati'c chain as :a substituent on the nitrogen atom thereof, 'they are "non-diffusing in photographic emulsions. :Due to their stability they may be incorporated either into a photographic :emulsion or in the developer notwithstanding alkaline nature :of such compositions.

.It is accordingly :an object of the present invention to utilize Q-naphthyl J-acid and the urethanes thereof in the iformation of :colorimages in -col'or photography.

*A' zfurther object of the present invention is to provide :a photographic silver halide emulsion with :color lformers which are urethanes of 2-- naph-thyl J -acid and which are non-difiusingin the emulsion. I

Other and further important objects of the inwention will become apparent :as the description I-proceeds.

The-compounds,theutilizationof which is contemplated herein, may The depicted "by the .iollowlug-formula:

*wherein R is hydrogen or =o-oR' Ian iaizali nnetal, 1i. e sodium, zpotassium, lithium and the like, ammonium or an organic base, i. e. pyridine, quinol'ine and the like, and the brominated derivatives of the aforestated urethanes.

It has been found that when employing the urethanes, it is preferable to use them in the silver halide emulsion rather than in the developer. When so used, it is imperative that the urethanes do not migrate from the emulsion layer in which they are located. In this connec tion it is to be observed that the urethanes possess a nuclear hydroxyl group and asa consequence yield dyes of the cyan type upon conventional color development. This in turn means that in compounding color formers with the urethanes, the urethanes must be located in the red sensitive layer. 1

In order to prevent migration or diffusion of the urethanes from the emulsion in which they are located, it is advisable to utilize compounds in which R is an aliphatic chain of at least 12 carbon atoms such as dodecyl, lauryl, tetradecyl, hexadecyl, octadecyl, palmityl and the like.

Examples of compounds embraced by the above formula and which we have found to be suitable for our purpose are: I

. Z-naphthyl J-acid. V

. Ethyl urethane of2-naphthyl J -acid.

. Hexadecyl urethane of 2-naphthyl J-acid.

. Lauryl urethane of 2-naphthyl J -acid.

. Dodecyl urethane of Z-naphthyl J -acid.

Butyl urethane of z-naphthyl Jeacid.

. Methyl urethane of 2-naphthyl J-acid.

. Octadecyl urethane of 2-naphthyl J-acid.

. The brominated derivative of hexa'decyl urethane of Z-naphthyl J-acid. v

10. The brominated derivative of octadecyl uretheme of Z-naphthyl J-acid.

Z-naphthyl J-acid is produced by heating Z-naphthylamine, sodium meta-bisulfite and J-acid, preferably while adding the J-acid portionwise to the reaction mixture.

The 2-naphthy1 J-acid thus obtained is converted into the urethanes by treating the same with the desired alkyl chlorocarbonate at low temperatures, preferably ranging from about 5 to 15 C. Desirably the reactants are vigorously agitated during the reaction. The desired low temperature is maintained by external cooling. Inasmuch as hydrochloric acid is split oif in forming the urethane, an acid binding agent should be present and this may be either an inorganic acid binding agent such as sodium hydroxide, potassium hydroxide, sodium acetate and the like, or an organic binding agent such as pyridine, quinoline or the like. Where an inorganic acid binding agent is used, and particularly if a low molecular weight chloroformate is employed, the reaction is effected in an aqueous medium. On the other hand, where a high molecular chloroformate is utilized, it is preferable to work with an organic acid binding agent in an organic solvent such as dimethyl formamide.

As already noted when using the urethanes containing a long aliphatic chain, preferably one having at least 12 carbon atoms, they are dispersed in a photographic silver halide emulsion. In order to incorporate the urethanes in the emulsion, one gram of the urethane is dissolved in 7 cc. of ethyl alcohol. The solution is then diluted with distilled water, neutralized-with sodium hydroxide and added to the emulsion. This procedure is followed in the subsequent examples.

Dye images are produced from the involved w 4 color formers by development with a conventional primary amine developer while using the color formers in non-difiusing form in a photographic emulsion or in diffusing form in said conventional developers.

The following examples will serve to illustrate the invention, the parts being by weight unless otherwise stated. These examples, however, are

illustrative only.

Example 1 Into a suitable vessel equipped with a rapid stirring apparatus, a refluxing condenser, and a heating element are placed 525 parts of 2- naphthylamine, 1400 parts of hot water and 665 parts of sodium metabisulfite. The mixture is heated to boiling and refluxed for 15 minutes. 100 parts of J -acid (the inner salt of commerce) .are introduced and the mixture is refluxed for 2 hours. Another 100 parts of J-acid are introduced and the mixture'is again refluxed for 2 hours. The addition-is repeated in the above fashion until a total of 500 parts of J -acid have been introduced. The resultant suspension is then refiuxedovernight. The hot mixture is filtered, taking on as much of the liquid as possible. The'wet press cake is returned to the vessel and extracted at 60-80" C. with a mixture of 2,000 parts water'and 500 parts 30% sodium chloride solution. The insoluble solid is collected by filtration and pressed as dry as possible.

The press cake is returned to the vessel and titurated with a mixture consisting of 3,000 parts of water and 2,000 parts of toluene at 7080 C.

- with vigorous agitation. Concentrated ammonium hydroxide solution is added until the aqueous phase is distinctly basic to phenol-phthalein. When all of the solid has gone into solution, the agitator is stopped and, after a suitable interval,

, the phases are separated. The aqueous phase is reextracted with 1,000 parts of toluene and is then diluted to a total of 6,000 parts. Sodium chloride solution (1,000 parts of 30%) is added and the clear liquid is neutralized with acetic acid and diluted to a total volume of 8,000 parts. The precipitate, which separates on standing and cooling, is collected by filtration and washed with a little ice water.

The wet press cake is dissolved in 8,000 parts of boiling water and decolorized with activated charcoal. The filtrate is treated with 200 parts of concentrated hydrochloric acid while being maintained at the boiling point. The resulting suspension is kept hot for one-half hour and is then filtered. The solid so obtained is washed with water until the wash water no longer runs soapy and is then dried. This is crude 2- naphthyl J-acid.

The crude Z-naphthyl J-acid obtained above is suspended in 2,000 parts of boiling glacial acetic acid and 800 parts of USP pyridine are added. The resulting hot solution is maintained at -100 C. for a period of 1 to 2 hours during which time the. crystalline pyridine salt of 2- naphthyl J-acid separates as a pale. yellow solid. .The material is collected by filtration, washed with acetic acid, and dried. If desired, the pyridine salt may be reconverted to the free acid by solution in sodium hydroxide and the addition of hydrochloric acid. There is obtained in the above manner a yield of 240 parts of pure dry pyridine salt of 2-naphthyl J-acid.

An exposed photographic silver bromide emulsion is developed in a conventional color forming developer containing about 1 gram of the 2- an'd'th'en' treated" with'iapart's; of ethylchlorof" carbonate. The mass 'is rapidly agitated and; kept a a proxima ely- -.9-,. .e st r el edblin'gfi and seeding, the sodium salt of the ethyl fire-' thane of 2=naphthyl gl=acijdfr separates and is collectedby filtration.

Anexposed silver bromide emulsion is developedj'a's inifixample lex'cep that the2'-naph thylfJ=ac1d; isreplaced'"by part; of the". ethyl urethane of2-naphthyFJ-acid. brilliant dye image is obtained upon working up the developed emulsion.

Example 3 The procedure is the same as in Example 2 excepting that the ethyl chloroformate is replaced by butyl chloroformate and the resulting butyl urethane of Z-naphthyl J -acid is employed in the developer in place of the ethyl urethane of 2-naphthyl J-acid.

Example 4 Into a suitable vessel equipped with a water separator and an agitator are placed 360 parts of dry dimethylformamide and 360 parts of dry benzene. The mixture is refluxed for a period of 2 to 5 hours, until no more water is obtained in the water separator. The mixture is then distilled until 1'70 parts of distillate have been obtained. 75 parts of the pure dry pyridine salt of 2-naphthyl J-acid (obtained in Example 1) is introduced and the mixture is heated with stirring until complete solution has taken place. The vessel is now equipped with a thermometer and means for the slow introduction of liquids and the content is cooled to 6 C. 2-hexadecylchloroformate (75 parts) is cautiously introduced, maintaining the temperature below 10 C. When a homogeneous solution has been obtained, pyridine (55 parts) is slowly added with good agitation, maintaining the temperature below 10 C. The resulting dark brownish red solution is stirred at 5 to 10 C. for a period of 2 hours. The temperature is then raised to 18-25 C. and the mixture is stirred for 16 to 24 hours.

The resulting suspension is evaporated to dryness with the aid of a good vacuum. The residue is extracted with 750 parts of dry benzene. The insoluble material is removed by filtration and discarded. The clear benzene filtrate is evaporated at 100 C. and 22 mm. pressure. The residue is dissolved in 1,000 parts of hot glacial acetic acid and the solution is cooled to 25 C. The insoluble waxy material which separates at this point is removed by filtration and discarded.

A mixture of 750 parts glacial acetic acid, 200 parts of acetic anhydrld? and 500 parts of conarmrest.aeratin hydroxide i emulsion thereareaddediogramfofthe Z-hexadejcyl urethane of Z-naphthyI J a'c'idprepared as' veloperjbleaching; and subsequent centrated hydrocloric acid is prepared andcooled and the mixture is maintained"at'20 C. for a period of 1 to 2h'ours The granular precipitate is cooled by filtration, washed with acetic acid, and dried. This solidisdissdlvedin 325 parts of ethyl alcohol. Lithium carbonate (50 parts) is added, and the mixture is stirred ffor one-half ness. The residue consists of the lithium salt of the 2-hexadecyl urethane 0f Z-naphthyl J -acid. To 100 cc. of a photographic silver bromide above. The emulsion" is'then coatedon a transparent film support and dried; ,After exposure,"

development in a conventional "color ior'ming' decolored'dyeimageisobtaifiedf t m 5.

Into a suitable vessel are placed 63 parts of the (lithium salt), 625;parts of aceticanhyiiride, 625 parts of glacial acetic acid and 63 parts of sodium acetate. The mixture is refluxed for 2 hours and is then cooled to 10-15 C. A solution of 16 parts of bromide dissolve in parts glacial acetic acid is slowly introduced at 10 C. with continuous agitation. After 2 hours, the mixture is evaporated to dryness, and the residue is crystallized from ethyl alcohol. There is obtained in this fashion a good yield of x-bromo-2-hexadecyl urethane of Z-naphthyl J-acid in the form of its sodium salt,

.5 gram of the brominated z-hexadecyl urethane of 2-naphthyl J-acid prepared as above is incorporated in 100 cc. of a photographic silver bromide emulsion in the manner described in Example 4. The emulsion is then coated on a transparent film support and dried. Upon processing the resulting film as above, a brilliant cyan dye image is obtained.

Various modifications of the invention will occur to persons skilled in the art. Thus, in lieu of employing the color formers for the production of quinoneimine dyestufif images in the color forming development method, they may also be employed to produce azo dyestuff images by the silver dye bleaching method. For example, a photographic emulsion containing one of the urethanes mentioned above and bearing a long aliphatic chain as a substituent, preferably one having at least 12 carbon atoms, is incorporated in a photographic silver halide emulsion in the ratio of 6 parts of the color former to 1 kilo of emulsion. The emulsion is then coated on a transparent film and the film exposed. After exposure, the film is developed in a black and White developer and is then bathed for a few minutes in a solution containing the tetrazo compound of benzidine-2.2'-disulfonic acid. A dyestuff is thereby evenly formed throughout the emulsion. The film is then treated in a conventional azo dye bleach bath to effect destruction of the dye at the silver image, whereupon the film is worked up according to the usual practice. A positive dyestufi image is thereby obtained in the film.

We claim:

1. The process of producing dyestuff images in an exposed photographic silver halide emulsion which comprises developing the emulsion with a d i lyj primarv aromatic amino developer in the presence of a compound selected from the class consisting of those having the following formula:

wherein R is selected from the class consisting of hydrogen and o -a'-on' B. being alkyl, and M is a member selected from the class consisting of hydrogen and a salt forming radical and the brominated derivatives of the aforestated urethanes.

2. A photographic silver halide emulsion containlng a color former fast to diffusion comprising a urethane of 2,-naphthyl J-acid of the following formula:

N t=o elk REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,367,531 Salminen et a1. Jan. 16, 1945 2,414,491 Tulagin Jan. 21, 1947 2,445,252 Tulagin July 13, 1948 

